Normally, a land-based data communication network transports information by using data packet switching. A wireless communication system, such as Global System for Mobile Communications (GSM), however, transports information in predefined or selected time slots over its wireless communication links. A GSM network transports data information by using circuit switching network. As a result, voice information is typically transferred in a circuit switched manner. A copy of GSM system specification and standards may be obtained by contacting European Telecommunications Standards Institute, 650 Rt. des Lucioles--Sophia Antipolis, Valbonne--FRANCE. A GSM communication system may provide general packet radio service (GPRS) along with traditional PSTN services according to the GSM standards. General packet radio services are provided via a data network operating based on data packet switching.
When voice information is transmitted in a wireless communication system, and the voice information is intended to be routed by data packet switching to reach a destination host, the voice information in the transmitter is treated like data packet information. As a result, a substantial number of overhead data bits are added to the voice information before its transmission. The amount of overhead data bits often times occupy most of the wireless communication bandwidth. Since the time slots of the wireless link have predefined and fixed duration and bandwidth, communication of voice information when treated like data information in the wireless communication system would occupy a larger bandwidth of the system capacity and a larger number of time slots than communication of the same amount of voice information when treated like voice information. Such a use of available system bandwidth is inefficient.
Therefore, there is a need for a method and apparatus for efficiently communicating voice information in a wireless communication system when the voice information is routed through a data network operating based on data packet switching.